At present, with the rapid development of mechanical automation, the transformer manufacturers are also increasingly adopting automatic machines for the production to ensure more precise and rapid manufacture of transformers. Furthermore, the mechanical equipment for production also evolves to be more simplified and user friendly. The transformer winding machine with the three-dimensional iron core of the prior art was designed to ensure the coil to be directly wound on the iron core. Therefore, how to effectively clamp the iron core during the winding process becomes an integral part of the design of the winding machine. Chinese patent for Utility Model No. ZL97217186.X, announced on Sep. 23, 1998, discloses a ring-type three-phase transformer winding machine, wherein the drum mechanism is composed of a roller and a gear. Each of two ends of the roller is equipped with a combined gear wherein the combined gear at the right end is composed of three gears and the combined gear at the left end is composed of two gears. The drum mechanism is positioned on one of posts of the ring-type three-phase transformer iron core, and is conveyed into the spatial center of the locating device through the progressive iron core advancing mechanism. The gear of the drum mechanism is meshed with the corresponding gear of the locating mechanism. The above technical solution is inconvenient for iron core winding and is complicated.